ScalaMock:如何模拟/存根方法每次调用返回不同的值？

使用ScalaMock,我想模拟/存根一个类方法,因此它将为每次调用返回一个不同的值(调用顺序很重要).

我可以用mock和实现这一点expects,但这将迫使我验证这些调用.

我可以这样做stub吗？

另外,我怎么能说"第一次返回X,然后总是返回Y"(两者都带有mock和stub)？

是的,这可以做到,虽然语法有点不直观:

    trait Foo { def getInt: Int }
    val fooStub = stub[Foo]

    (fooStub.getInt _).when().returns(1).noMoreThanOnce()
    (fooStub.getInt _).when().returns(2).noMoreThanOnce()
    (fooStub.getInt _).when().returns(3)
    (fooStub.getInt _).when().returns(4)

    assert(fooStub.getInt == 1)
    assert(fooStub.getInt == 2)
    assert(fooStub.getInt == 3)
    // Note that it's fine that we don't call it a fourth time - calls are not verified.

使用.noMoreThanOnce()而不是.once()很重要,否则会导致调用被验证.还有一个.noMoreThanTwice()方法,但我认为没有.noMoreThanNTimes()或任何等价物.

这里是如何做"第一次返回X,然后总是返回Y"的模拟和存根:

    trait Bar { def getString: String }
    val barMock = mock[Bar]

    (barMock.getString _).expects().returning("X")
    (barMock.getString _).expects().returning("Y").anyNumberOfTimes()

    assert(barMock.getString == "X")
    assert(barMock.getString == "Y")
    assert(barMock.getString == "Y")

    val barStub = stub[Bar]

    (barStub.getString _).when().returns("x").noMoreThanOnce()
    (barStub.getString _).when().returns("y")

    assert(barStub.getString == "x")
    assert(barStub.getString == "y")
    assert(barStub.getString == "y")